immunology II Flashcards
acquired immunity is broken down into two parts. name them
- active: own antibodies are made
- natural: exposure to infectious agents
- artificial: immunization
- passive: ready-made antibodies
- natural: maternal antibodies
- articial: antibodies from other sources
humoral immunity consists of what components
- B cells
- antibodies
cell-mediated immunity consists of what components
- T-cells
- APC
- dendritic cells, macrophages, B-cells
what are the 4 attribute of adaptive immune system
-
antigen specificity
- targets specific pathogens
-
high diversity
- pathogens recognized and targeted
- immunologic memory
-
needs to be activated
- activated by exposure to antigens
epitopes
distinctive markers of antigens
antigens
markers of non-self
cells of adaptive immune system are derived from what common cell
Lymphoid stem cell
Name the primary lymphatic organs and their function
where B cells and T cells mature and differentiate
- Bone marrow (B cells)
- Thymus (T cells)
name the secondary lymphatic organs
- Spleen
- Lymph nodes
- Tonsils
- MALT: mucosal associated lymphoid tissue
function of secondary lymphatic organs
- where mature antigen-specific B and T cells interact
- interact with eachother and antigen presenting cells
Humoral immunity:
- mediated by:
- defense against:
- mediated by: B cells
- defense against: Extracellular pathogens
Cell mediated immunity
- mediated by:
- defense against:
- mediated by: T cells
- defense against: Intracellular pathogens
function of major histocompatibility complex (MHC) - known as HLA (human leukocyte antigen)
- cell surface molecules
- allow cells to recongize each other
which cells have MHC-I
virtually all cells
which cells have MHC-II
- B-cells
- dendritic cells
- activated macrophages and thymic epithelial cells
MHC II molecules present antigen to what cells
T helper cells
T helper cells have what receptors?
- T- cell receptor: responsible for recognizing antigens bound to MHC II
- CD4 co-receptor
how do T-helper cells become activated
- T-helper cells look for APC
- binding of MHC II molecule with antigen activates T-helper cell
- activated T helper cell activate other cells by releasing cytokines
where do humoral immunity take place
secondary lymphatic organs
how do B cells come to display antigens via MHC II
- B cell sees an antigen
- binds to and engulfs antigen
- processes antigen and displays fragment as MHC II
how do B cells differentiate into plasma and memory cells
- B cells interact with activated T helper cells which co-stimulate B cells to differentiate into plasma and memory cells
structure of antibodies
- 2 identical heavy H chains
- 2 identical light L chains
- tips of “Y” are variable: antigen binding site
Primary response of humoral immunity
- B cells first encounter with antigen
- require T-helper cells to activate
- B cells proliferate and differentiate into plasma and memory cells
function of plasma cells (differentiated form of B cells)
make antibodies
what antibody is produced first? second?
- IgM “Immediate”
- IgG follows
In humoral immunity secondary response (subsequent encounter of same antigen), previously generated B memory cells activate rapidly. which antibody is most involved?
IgG
direct action mechanisms of antibodies: binding of antibodies to antigens inactivtes antigens by what 5 mechanisms?
- neutralization: neutralizes toxins; blocks binding of viruses and coats bacteria
- agglutination of microbes
- precipitation of dissolved antigens
- opsonization: provides “handles” for phagocytosis
- activation of complement system
which class of immunoglobins is primarly involved in secondary response
IgG
which class of immunoglobins are the only IgG which cross the placenta
IgG
half life of IgG
21 days
which class of immunoglobins is the major antibody against carbohydrates on bacterial cell walls
IgM
which class of immunoglobins is the predominant antibody formed by fetus and neonate
IgM
which class of immunoglobins is able to diffuse from vasculature
- IgG: small size
structure and half life of IgM
- pentamer
- half-life: 5-10 days
structure and half life of IgA
- monomer or dimer with J chain
- 6 days
location of IgA
mucosal areas
- gut, respiratory tract, urogenital tract
structure and half life of IgD
- monomer
- 3 days
location of IgD
on mature B cell membranes; required for B cell activation
structure and half life of IgE
- monomer
- 2 days
function of IgE
- binding of IgE on mast cell or basophil results in release of histamine
- defense of parasites
which Antibodies are responsible for type II hypersentivity reactions
- antibodies bind to antigens on patient’s own cell surface or fetus cells
- IgM and IgG
which class of antibody is responsible for type I hypersensitivity reaction
- allergy, gives, anaphylactic rxn
- IgE
what are the types of T cells
- T-helper cell
- T-memory cell
- T-regulatory (suppressor cells)
- cytotoxic T cell (T killer cell)
- Natural T killer cell
function of T-regulatory (suppressor cells)
prevent immune reactions from getting out of hand
T killer cells (cytotoxic T cells) are activated how
by T helper cells
receptors on T killer cell
- T cell receptor
- CD8
what role do T cells have in Diabetes Mellitus Type I
- T cells target beta cells of pancreas
- patient can no longer make insulin
what role do T cells have in Multiple Sclerosis
- T cells target myelin proteins
- destruction myelin sheath
function of HIV virus
- destroys T helper cells
- impairs both humoral and cell-mediated immunity
end product of activation of complement
MAC: membrane attack complex
how is complement activated
C1 binds to antigen-antibody and activates the cascade
